Several years back, I used to hear my local Army National Guard helicopters on a 41 mHz frequency. I used PL tone 151.4, but I remember reading that "new squelch" was actually 150.0 hZ. Anyway, is there likely to be much activity on those frequencies these days or have they all gone encrypted and/or to frequency hopping spread spectrum by now?

Military users could pop up practically anywhere in the "low band", roughly from 30-54MHz. Every area is unique. Back in the old days, there were quite a few freqs I could point to and say they were common-use, but not so much lately, at least with the ones I have programmed.

Check the RR database, local monitoring groups (amateur radio clubs, Yahoo Groups, local forums, etc), and of course it helps to have an antenna with good gain on that part of the spectrum...put your scanner in "search" mode, sit down with a pad of paper and a coffee, and have at it!

Search 30-87.975 in 25 kHz steps. Depending on where you are 54-72 and 76-88 MHz could have TV stations (ch 2-6) and not be usable by the military.
See https://wiki.radioreference.com/inde...s#29.89-50_MHz for the low band frequency ranges allocated to the federal government.

In Southern CA where I live and before the digital upgrade we had a TV channel 2 that covered roughly 54 to 60MHz continuous with its video and audio carriers. I was offloading one weekend and ran across a military convoy of HUMVEEs and I happened to have a 1.8 to 76MHz PRC-70 military manpack with me that trip.

When we passed the slow moving off road convoy I held up the H-250 military handset for my radio, which the guys in the front vehicle recognized and I yelled "what frequency are you on!" They motioned with one hand, five fingers out and flashed that four times. I was confused but my partner on that trip said lets try 55.55MHz so we did and I made a call to the hummer guys. To my surprise they answered back and that was their convoy frequency for their outing that day. It was right in the middle of TV channel 2 used in that area, but for the close range they had between vehicles, it didn't really matter. So you never know where they will show up.
prcguy

Quote:

Originally Posted by nd5y

Search 30-87.975 in 25 kHz steps. Depending on where you are 54-72 and 76-88 MHz could have TV stations (ch 2-6) and not be usable by the military.
See https://wiki.radioreference.com/inde...s#29.89-50_MHz for the low band frequency ranges allocated to the federal government.

Where is there even enough land to put up a 41 milihertz longwire, never mind a helicopter big enough to carry one? Then again I hear they're doing amazing things with computers and DSPs these days.

Think he typoed MHz..... But you would need an chinook or skycrane for an mHz system ant.. LOL You can still find some comms on the 41.XX MHz range, but most now use civilian aviation, 138 - 144 MHz, and UHF. There is some spread spectrum, and some encryption... But not as much as you would think. Also, in areas that have statewide TRS, NG uses that for ops also.

None of the following is meant to discourage, but merely to inform. This post got a bit outta hand

closing in on 2 years now of fairly heavy focusing on low-band FM has brought surprising results, but at a cost of non-trivial time and effort. gonna just hit the highlights

My observations:

1. They're out there, but casual scanning will be disappointing for most i think. as most people have a life with time commitments that are incompatible with the time and effort expenditure that were required for me to achieve my results.

2. You have to be close for most anything that has a local origin. Skip from fort hood is almost easier
than the transmitter next door.

2. 30-50MHz is the best bet. 50-54- the time wasted due to ham activity (no offense intended ham's) i have concluded makes it too tricky.

3. The standard conventional wisdom and suggestions are where you'll do best starting out.

4. After you have gotten the hang of it, forget #3

5. 50khz seems to be the best bang for your buck.

6. #5 is right until you catch a xx.18 or a xx.88 which conform to neither 25 or 50khz spacing. (but you won't catch me wasting my time doing a 10khz search, and only rarely a 5khz if a turbo search function is possible.)

7. EVERYTHING between 30 and 87.975 apparently is fair game. if a rural school bus gets stepped on, the big green machine doesn't care. neither do i. i just wish the school board would get em some new radios and quit clogging up my scanners.

over 54 is active too, i just dunno how much. Scanners as a general rule don't cover this range and those that do are unlikely to be utilized for this niche. those are likely some reasons there are few reports of use. in 3 months with my beautiful new-to-me BR330XT i have snagged 2 60's. but only on one occasion for each has chatter been heard so far and the finds were 2 days apart. now if you check out this excellent site, you'll see that, at least in his area, it seems over 54 is as active as under 54

8. infrequent use, short range propagation, and normally low altitude of helos make life difficult (the majority of my experience with low band has been 90% helo/osprey with ground to helo and ground to ground rounding out the rest. well HAHO training used low-band but i dunno how to classify that... i mean it was air to air...)

9. but on the bright side, between 30-50MHz, i have discovered exactly 20 freqs (as of last month) used for voice comms in this period. this breaks down to an average of about 1 a month, though the finds were often clustered. i have also heard a handful of others mentioned (ie: "what freqs are we using this time?" "XX.XX and XX.X") but never heard personally used. Of those 20, 16 were 30's and 4 were 40's. 36 and 38's seem to get heavy rotation and there is a .75 ending on about a third of the total with XX.X00 being about another third. now these are just what i have personally noted and confirmed. BUT, one should know that i have only recently, and very begrudgingly, started searching in 25kHz steps regularly between 30-50. I have normally stuck with 50kHz steps in searching, so that should be kept in mind as to the possible bias in my breakdown. the .88 and .18's were only found due to signal stalker catching them (confirmed via 2 other scanners as correct) and both were OH-58D's which are sadly no longer around.

10. prob the most important suggestion tho is - Forget About Tones - 151.4 does let 150.0 through, no question. but use that as a guide. search and store's that show a 151.4, add them to your scan list. put the frequency in and set tone to search and you'll see how rarely anything pops up. usually they are directly over my head or have been talking for a loonnng time before the scanner shows a tone. btw the first time i picked up the famous fort hood range control 30.45FM(i think thats it), my bc346xt showed...PL146.2. everytime. for a solid half hour. only had one scanner at the time so couldn't do a pass through test but it is something to keep in mind.

basically the only reasons to ever use a tone setting is if you have a spurious RF issue, which is often a problem, or on the off chance of there being other users. example: 39.95 has been reported as in use by the military in my area, however 100miles away from me, stokes co school buses use 39.96. bleeds right on through. therefore i have to set a tone on 39.95. i have never heard a peep on it either.

if you have read to this point, you better check the time, cause you are late for something. as am i...

Several years back, I used to hear my local Army National Guard helicopters on a 41 mHz frequency. I used PL tone 151.4, but I remember reading that "new squelch" was actually 150.0 hZ. Anyway, is there likely to be much activity on those frequencies these days or have they all gone encrypted and/or to frequency hopping spread spectrum by now?

As some one said above, these guys pop up any where on low band. Just last week, I had two Blackhawk helicopters passing nearby BSing on 45.00 mhz FM. A public safety channel. The 32 and 38 mhz area seems to be popular with helicopters around here also.

In Southern CA where I live and before the digital upgrade we had a TV channel 2 that covered roughly 54 to 60MHz continuous with its video and audio carriers. I was offloading one weekend and ran across a military convoy of HUMVEEs and I happened to have a 1.8 to 76MHz PRC-70 military manpack with me that trip.

When we passed the slow moving off road convoy I held up the H-250 military handset for my radio, which the guys in the front vehicle recognized and I yelled "what frequency are you on!" They motioned with one hand, five fingers out and flashed that four times. I was confused but my partner on that trip said lets try 55.55MHz so we did and I made a call to the hummer guys. To my surprise they answered back and that was their convoy frequency for their outing that day. It was right in the middle of TV channel 2 used in that area, but for the close range they had between vehicles, it didn't really matter. So you never know where they will show up.
prcguy

So from my homework, 30.00 - 87.975 FM mode, 25Khz search step size.
I did this for awhile in search mode, then figured out I could simple create in excel or Freescan, an auto-populated table of frequencies starting at 30.00Mhz to 87.975Mhz. Since I favor Uniden's I created three conventional systems:

87 FM 30-49 SRCH
88 FM 50-74 SRCH
89 FM 75-88 SRCH

I put a number in front of every named system in the radio, so i remember it, and it's quick key.
Now, each system has a group that has all the frequencies in 25Khz increments for its range. So, for the first system:
30.000
30.025
30.500
all the way to 49.975

I did the same for the remaining systems named above. This has proved to be a very fast way of tagging activity. If a flight of six copters rumbles over the house, I grab the radio, press the quick key for which range I want to scan, and wait with laser focused attention. This has worked for me, and made most sense based
on the speed at which the radio scans channels per second.

I have found numerous copter "inter-phone" activity between 30-49.975, some army convoys on 50.025,
and some stuff up around 66Mhz.

Last time I heard milcom activity in the 60 mhz area was in the late 90's when the A10s out of Barnes used 64.10 and 64.45 FM while working at the Warren Grove Range here in NJ. 51.50 comes up sometimes with helo activity.

Been listening to the local Army National Guard for years. Local air unit and engineer units.But have never heard the Army Reserve unit (Military Police) even when I saw a guy using an handset once in a Hum-vee, The frequencies do change but change can be slower than a glacier.